Dirk Thierbach wrote :
> I think I wouldn't use objects at all in this situation. You're trying
> to model the location-tree of "physical" things. A tree must be uniform
> in its contents, but you want to put different things into it. That
> means you must use an algebraic type, or variants. I'd probably either
> use a zipper, or connect the tree nodes with "refs" for the non-pure
> version. 

You are preaching to the choir.  I'm not Gerd Stolpmann and I don't use
objects very much because every time I try I get seven-page-long errors.

However it seems that objects could be actually useful in situations
where you have a hierarchy of objects with behaviours, such as a graphical
user interface made of widgets, or, say, a text adventure.

-- 
Berke DURAK